This chapter attended as a significant and through introduction to and a validation for the chosen research approach. The chapter discussed the particulars related to factors affecting consumer behavior of fast food stores in Future Park Rangsit. Moreover, To find out the consumer behaviors that affect consumer decisions in fast food stores such as 4P's marketing (price, product, promotion, place) on customer. The chapter covered the subsequent research areas including; model or theoretical framework, hypotheses and research questions for this study, studying area, population and sample selection, measurement instrument, data collection for this study, and data analysis.